This invention relates generally to cellular telephone network services and management. More specifically, it relates to systems and methods for distributing real-time cellular telephone information in the course of providing location-based services.
There are many potential uses of real-time cellular telephone location information. For example, U.S. Pat. No. 5,512,908 to Herrick mentions the application of cellular location information to 911 dispatching, tracking unauthorized cell phone usage, and tracking or locating commercial and/or government vehicles. U.S. Pat. No. 5,327,144 to Stilp et al. also mentions various applications of mobile location information, such as locating lost or stolen vehicles, assisting lost motorists, and dispatching emergency vehicles. These services have not been realized, however, due to several difficulties. First, the conventional methods of location finding, which are based on techniques such as direction finding (DF), time of arrival (TOA), and time difference of arrival (TDOA), cannot accurately and reliably locate transmitters in severe multipath environments. Without reliable location information, it is not possible to provide location based services. A solution to this fundamental problem, however, is disclosed by Hilsenrath et al. in U.S. patent application Ser. No. 08/780,565 now U.S. Pat. No. 6,026,304 which is incorporated herein by reference. Their approach, which takes advantage of multipath signals rather than attempting to mitigate or avoid them, measures a signal signature and determines a location by matching the signature with a calibrated database of signature-location pairs.
Another difficulty facing the realization of location-based services is the expense of communicating the location data to various third party services. In conventional systems, dedicated communication lines are established between the location finding equipment and the third party subscribers in order to transfer the constantly changing location data. Continuously maintaining these lines, especially over long distances, can be very expensive. In addition, if there are many location-based services or many different subscribers, many expensive dedicated lines and/or many differing protocols for communication may need to be devised and deployed to provide the information to each specific location-based service and/or subscriber. The creation and maintenance of these dedicated lines and protocols can be very expensive and inconvenient.
Accordingly, it is a primary object of the present invention to provide a method for conveniently and inexpensively communicating location information in real time to third party service providers. It is another object of the invention to provide such a method that is simple to use and allows subscribers to be added and deleted easily and inexpensively. It is another object of the invention to provide for the realization of many cellular network services and management applications that have heretofore been unattainable due to the absence of a simple and inexpensive technique for communicating real-time cellular telephone information to service providers. These and other advantages will become apparent from the following description and accompanying drawings
The present invention provides a system for easily and inexpensively distributing real time location information of cellular telephone users to various third party information subscribers. A dynamic database of current cellular users is created and is maintained at a central server machine. The database has a list of caller entries, where each entry typically comprises a user ID number, such as a phone number, mobile ID number, and/or handset serial ID. The entry also includes, for each user ID number, a user location identifier such as a latitude and longitude, a sector number, a caller or called phone number and/or a street address. Each entry can include additional information as well, such as a current base station for the user and a most recent registration time of the user.
The database is maintained on an HTTP server connected to the internet. Registered third party information subscribers are given access to the database by means of standard HTTP protocols that ensure authentication and provide encryption for security. Using caller ID or other means for obtaining a caller""s phone number, the third party subscriber can obtain, via a simple internet query, the current location of the caller by submitting the phone number to the HTTP server using an HTML form. Standard software on the central server machine verifies the authenticity of the subscriber, looks up the location information in the database, and returns the information to the subscriber. The subscriber can then use the location information to provide any of a wide range of services to the caller, or to dispatch emergency vehicles to the location of the caller. In addition, the server can directly provide many location-based services to callers.